The present invention relates to a tire emulator which reproduces the effect of a rolling pneumatic tire on the vertical input to a vehicle spindle on spindle coupled road simulators.
U.S. Pat. No. 4,658,656 illustrates a multiple axis test machine that reproduces road excited vehicle vibrations. An actual pneumatic tire is mounted to provide simulated loading, including "wheel hop" phenomenon. The loads from road travel onto a test vehicle spindle can thus be reproduced.
U.S. Pat. No. 3,713,330 illustrates a simplified multiple axis test machine with a rigid vertical link transmitting the simulated vertical road input to the spindle of the vehicle.
The present device comprises a tire emulator that replaces the pneumatic tire of U.S. Pat. No. 4,658,656 and provides a simple direct replacement of the vertical link of U.S. Pat. No. 3,713,330.
The importance of tire emulation in road simulation is described in an article entitled "Integrating Simulation Technology into Automotive Design and Validation Processes" by Stephen A. Nolan and Nigel A. Linden (SAE Technical paper No. 871941, 1987). This invention adds in a simple manner the advantages of a tire coupled simulator to the advantages of a spindle coupled simulator. In particular, it allows for dynamic response changes (as provided by the tire in the real case) due to suspension component variations during the test and it requires less power on the power intensive vertical input simulation. It simulates the real case "wheel hop" and "rim strike" dynamic vertical load input changes. Additionally, through manual or automatic control adjustments, it emulates the characteristics of a rolling tire which are different than a static tire.